Biosimilar Interchangeability and Substitution in the US: What Comes Next?

In 2009, Congress created a regulatory pathway for biosimilars to encourage competition and address rising spending on biologic drugs. One barrier to adopting biosimilars in the US is that the FDA has traditionally required additional testing for biosimilars to be deemed interchangeable with the original biologic. This analysis reviews the history and current status of biosimilar regulation in the US, concluding that changing the FDA's interchangeability standards-as proposed by some policy makers-is a potentially useful but likely insufficient step to improve biosimilar competition in the US. Other policy options include more state laws allowing pharmacists to automatically substitute biosimilars, addressing strategies by payers and pharmacy benefit managers that inhibit biosimilar competition, and implementing more widespread education of clinicians and patients to build confidence about biosimilars. Other policies to ensure the affordability of biologic drugs include expanding Medicare's price negotiation to cover biologics with or without biosimilar competition.